JPH01143341A - Superconductive connecting body device and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain an integrated superconductive connecting-body device by forming the first and second ribbon-like thin films on a substrate and by taking out current from the side surface of groove of the first ribbon-like thin film to the second ribbon-like thin film. CONSTITUTION:A ribbon-like superconductive first thin film wiring 110, grooves 140A and 140B which were opened from the surface of a silicon oxidation film 120, and the second superconductive thin film wiring 160A and 160B connected to a groove 140 are formed on a substrate 100. Current which has flowed from the wiring 160A, where current flows isotropically, uniformly flows from a side surface 150A of the groove part 140A which was formed on the aeolotropical wiring 110, and is taken out of the side surface 150B of the groove part 140B into the wiring 160B in a good condition. Thus, an integrated superconductive connecting-body device can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a superconducting connector device using a superconductor etc., and in particular to a structure of a superconducting connector device incorporating a superconductor thin film such as a compound. and its manufacturing method.

Conventional technology Conventionally, niobium nitride (NbN) and germanium niobium (Nb
3Ge), but the superconducting transition temperature of these materials was at most 24°. A Ba-La-Cu-0 system of perovskite ternary compounds has been proposed as a material expected to have an even higher transition temperature.

However, according to recent research, Y-Ba-Cu-
It has been suggested that 0-based materials may exceed liquid nitrogen temperatures (
M., Ni, Wu et al., Physical Review Letters.
) Vol, 58, No. 9, PP, 908-9
10 (1987)), superconducting compounds having a transition temperature of 900 or higher have actually been reported.

Problems to be Solved by the Invention Single-crystalline superconducting thin films have a higher critical current density in their interconnects than polycrystalline superconducting thin films, and furthermore, they are active rather than passive elements such as interconnects. It was also used as the active region of devices, and its practical application was urgently needed. Y-Ba
- Even if thin films of Cu-0-based compounds are formed by sintering or sputtering, it is relatively easy to obtain ceramic powders or lumps that exhibit superconductivity, but the crystal axis with a large critical current It was difficult to obtain a thin film with uniform single crystallinity. However, to the knowledge of the present inventors, even in the sputtering method, sapphire (α-AI2
03) found that using single crystals such as magnesium oxide, spinel, silicon, gallium arsenide, etc. is very effective for forming superconducting thin films with good single crystallinity.

Furthermore, in the thin film formed in this way, the C axis of the crystal tends to be perpendicular to the plane of the substrate, and the carrier density of the superconducting current flowing in this plane direction (direction perpendicular to the C axis) is , direction along the C-axis (direction parallel to the C-axis)
It was found that the carrier density is several times larger than the carrier density of the superconducting current flowing in the . That is, it was easy to flow a superconducting current in a direction perpendicular to the C-axis, and it was difficult to extract a superconducting current in a direction parallel to the C-axis. Furthermore, the coherence length of superconductivity is several tens of nanometers in the direction perpendicular to the C axis, and C
In the direction parallel to the axis, on the order of several nanometers, similarly,
It is known that there is a difference of several times.

In this way, when a thin film superconductor made of a compound such as Y-Ba-Cu-0 is used, for example, for wiring of an integrated circuit superconducting connection device, superconductivity tends to flow in the horizontal direction of the substrate. There was a problem that anisotropy of the current was easily observed and it was difficult to extract the current in a direction perpendicular to the plane.

Means for Solving the Problem In order to solve this problem, the present invention provides a first ribbon-shaped thin film formed on a substrate and full of conductive anisotropy that easily flows in a plane parallel to the substrate. , a groove formed from the surface of the first ribbon-shaped thin film, and an isotropic second groove formed in connection with the groove and having no conductive anisotropy.
A superconducting connector device comprising: a ribbon-like thin film; forming a first ribbon-shaped thin film having conductive anisotropy that tends to flow in parallel plane directions;
forming a groove in the surface of the ribbon-shaped thin film; and forming a second isotropic ribbon-shaped thin film with no conductive anisotropy, which is connected to the groove; Provided is a method for manufacturing a superconducting connector device, characterized in that a current is taken out from the side surface of the groove of the ribbon-like thin film to a second ribbon-like thin film.

Function: By the method of the present invention, for example, Y-Ba-Cu-
By forming a groove from the surface of the anisotropic ribbon-like thin film of a zero-based material, it becomes easy to extract current flowing in a plane parallel to the substrate from the side surface of the groove. . Therefore, it is a good idea to form a conductive film in the form of a ribbon-like thin film without anisotropy in contact with the side surfaces of this groove. At this time, if these two ribbon-like thin films exhibit superconductivity, multilayer wiring without electrical resistance can be realized. In addition, if the width of the groove is larger than the width of other parts of the ribbon-like thin film, the cross-sectional area of the current extraction region can be increased, so that the current density can be reduced from the narrow wiring part with high current density. This enables connection to thin films with low anisotropy. Considering this point as well, it is preferable that the width of the groove is larger than the width of other wiring portions of the ribbon-shaped thin film. Furthermore, in order to extract the maximum amount of current from the side surfaces of the groove, it is preferable to etch the groove to the bottom of the anisotropic ribbon-like thin film to maximize the area of the side surfaces. On the other hand, if the coherence length of the thin film in the direction perpendicular to the plane of the anisotropic thin film is relatively large compared to the thickness of the thin film, it is not necessarily necessary to etch the groove until it reaches the bottom surface of the thin film. In other words, even if a thin film with a thickness equal to or less than the coherence length remains under the groove, superconducting current can be extracted from the bottom of the groove.

EXAMPLE Hereinafter, the structure of a superconducting connector device using superconducting wiring according to the method of the present invention will be described in detail as a first example with reference to FIG.

Y-Ba- formed on a substrate 100 of crystalline sapphire (α-A12o3) at a substrate temperature of 700-10000c and with the C axis aligned in a direction substantially perpendicular to the plane of the substrate.
A ribbon-shaped superconducting first thin film wiring 110 made of Cu-O based crystal with a thickness of approximately 1000 nanometers, and grooves 140A and 140B opened from the surface of a silicon oxide film 120 covering the surface of this thin film. And second superconducting thin film wirings 160A and 160B of polycrystalline Y-Ba-Cu-0 system crystal (formed at a substrate temperature of 200-5000 C) and having a thickness of about 1500 nanometers are connected to this groove 140. is formed. Here, the portions having a thickness equal to or less than the coherence length in the direction perpendicular to the thin film wiring 110 are the groove portions 140A, 140.
It may be left in the lower part of B. Here, superconducting wiring 1
60C is a wiring that passes over the superconducting wiring 110.

According to the structure of the present invention, the wiring 16 allows current to flow in the same direction.
The current flowing from 0A flows through the anisotropic superconducting wiring 110.
The wiring 160B flows uniformly from the side surface 150A of the groove portion 140A formed in the
It was taken out in good condition. In such an arrangement, if an opening is formed in the oxide film 120 under the wiring 160C and a groove is not formed in the wiring 110, the wiring 110 and the wiring 160C
Even if the wiring 160A is connected to the wiring 160A, most of the current is extracted from the side surface 150B of the groove 140B to the wiring 160B without flowing into the wiring 160C.

The structure of a superconducting=8-connector device using superconducting wiring according to the method of the present invention will be described in detail as a second embodiment with reference to FIG. 2.

As shown in the top view of FIG. 2, it has the same configuration as the first embodiment of FIG. It has become. The large side grooves provided the following effects.

Current flows from the narrow wiring part to the groove part with a large cross-sectional area without being affected by the anisotropy of conductivity in the wiring part, so the current flows from the thin film part with high current density to the thin film with low current density and no anisotropy. It is possible to connect large currents to

A third embodiment of the method for manufacturing a superconducting connected body device using superconducting wiring according to the method of the present invention is shown in FIGS. 3(a) to 3(a).
This will be explained in detail with reference to (C).

As shown in Figure 3 (a), crystalline sapphire (α-A1
On the substrate 100 of 203), at a substrate temperature of 700-1000°C, a Y-Ba-Cu-0-based crystal with a thickness of about 1000° C. is placed such that the C axis is aligned in a direction substantially perpendicular to the plane of the substrate.
A nanometer ribbon-shaped superconducting thin film is formed, a ribbon-shaped wiring 110 is formed by a normal photoetching process and physical etching using argon, etc., and then a silicon oxide film or the like is coated on the entire surface. An insulating film 120 was formed.

As shown in Fig. 3(b), a depth of about 80 mm is etched by a normal photoetching process and physical etching using argon, etc.
Groove 14OA with nearly vertical sides of 0 nanometers
, 140B is formed on the entire surface, polycrystalline (substrate temperature 20
A superconducting thin film 160 of approximately 1500 nanometers thick is deposited using a Y-Ba-Cu-○ system crystal (formed with 0-5006C), and resist patterns 180A, 180B, and 180C are further formed by a normal photoetching process. did.

As shown in FIG. 3(C), resist pattern 180A,
Using 180B and 180C as masks, superconducting thin film 160
A ribbon-shaped superconducting wiring 160A is formed by physical etching using argon or the like.

160B and 160C were formed, and the resist 180A and the like were removed. Here, superconducting wiring 160C is superconducting wiring 1
This is a wiring that passes over 10.

As described above, according to the manufacturing method of the present invention, the current flowing from the wiring 160A through which the current can flow isotropically is
10, uniformly flows from the side surface of the groove 140A formed in the groove 140B, and flows from the side surface 150B of the groove 140B to the wiring 160B.
It was taken out in good condition. Note that the base body 100 may be made of silicon semiconductor crystal.

Effects of the Invention According to the structure and manufacturing method of the present invention, in particular, superconducting thin films having anisotropy of current can be well connected to each other while wiring, elements, etc. are formed, and an integrated superconducting connection body can be produced. We are now able to provide the equipment.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a first embodiment of the device according to the present invention, FIG. 2 is a plan view of main parts showing the second embodiment of the device according to the present invention, and FIGS. 3(a) to (c) 1 is a series of process cross-sectional views showing an example of the manufacturing method according to the present invention. 100...Base, 110.200...Anisotropic superconducting film, 120, 220...Insulating film, 140...Groove, 1
50... Side surface of the groove, 160... Isotropic superconducting film,
180...Resist.

Claims (7)

[Claims] (1) A first ribbon-shaped thin film formed on a substrate and exhibiting conductive anisotropy that tends to flow in a plane parallel to the substrate; and a groove formed from the surface of the first ribbon-shaped thin film. , an isotropic second ribbon-shaped thin film with no conductive anisotropy formed in connection with the groove,
A superconducting connector device characterized in that a current is taken out from a side surface of a groove of a first ribbon-like thin film to a second ribbon-like thin film. (2) The superconductor according to claim 1, wherein the width of the groove of the first ribbon-like thin film is larger than the width of other parts of the first ribbon-like thin film. Connection body device. (3) A superconducting connection according to claim 1 or 2, characterized in that a side surface of the groove section perpendicular to the current flow crosses at least the first ribbon-shaped thin film. body equipment. (4) Claim 1, characterized in that the bottom surface of the groove penetrates at least the first ribbon-shaped thin film.
2. A superconducting connector device according to any one of Item 2 and Item 2. (5) Thickness of the thin film left between the side surface of the groove and the end of the first ribbon-like thin film, and thickness of the thin film left between the bottom of the groove and the bottom of the first ribbon-like thin film. The superconducting connector device according to claim 3 or 4, wherein the coherence length in the direction perpendicular to the substrate is at least equal to or less than the coherence length. (6) forming a first ribbon-shaped thin film on the substrate, which exhibits conductive anisotropy that easily flows in a plane direction parallel to the substrate, and forming grooves from the surface of the first ribbon-shaped thin film; and a step of forming an isotropic second ribbon-shaped thin film with no conductive anisotropy connected to the groove, the side surface of the groove of the first ribbon-shaped thin film being connected to the groove. A method for manufacturing a superconducting connector device, characterized in that a current is extracted from a second ribbon-shaped thin film. (7) The method for manufacturing a superconducting connector device according to claim 6, wherein the ribbon-shaped thin film is a superconducting film.